Any team looking for long term success...and with half a brain, does not subject it's drivers to this numbering system.
You can think it. You'd just better not put it down on paper...not if you're smart anyway.
It generally does not work very well. I've only seen it work a few times in the 41 years I've followed this sport.
Right off the bat, the psychologically impact dooms the number two driver. That driver usually scores much less than the number one. It also causes a lot of animosity in teams, even though it's usually not apparent to TV cameras.
It's okay to put more resources behind the leading driver when the other is mathematically out of the picture. Relegating a driver who's very much a contender to give up his quest by labelling him with a number two role, only causes 'bad-blood' in teams.